Typically, turbo-apparatuses, such as compressors, turbines, and fans, include blades to be rotated at a predetermined speed.
For example, a fan has several tens of blades.
Also, in the case of a gas turbine engine, if combustion gas, produced as high-pressure air supplied from a compressor, is burned in a combustion chamber provided in the gas turbine engine, the high-pressure and high-temperature combustion gas is directed into a turbine, thereby being used to rotate a plurality of blades provided in the turbine, a rotating force of the blades being used to generate power.
That is, the gas turbine engine has several thousand blades.
The above-described turbo-apparatuses, such as compressors, turbines, gas or steam turbines and fans, have a feature in that a total pressure downstream of a blade is periodically changed according to rotation of the blade.
Specifically, rotation of a blade causes a pressure wave, similar to a sinusoidal wave, downstream of the blade.
However, when the blade is installed in the turbo-apparatus, it is impossible to easily observe the blade from the outside with the naked eye.
That is, visually observing the interior of the turbo-apparatus has conventionally not been allowed in a state wherein the blade is rotated at a high speed and therefore, there is a problem in that, if any blade is broken in the turbo-apparatus, it is impossible to rapidly recognize the broken blade.
Upon the breakage of any blade, conventional turbo-apparatuses exhibit gradual deterioration in performance. Moreover, broken blades may impair balance of a rotor included in the turbo-apparatus, causing fatal breakage of the entire apparatus.
For this reason, recently, there is a need for a technology to monitor the presence of a broken blade(s) used in a turbo-apparatus in real time.
The above information disclosed in this Background Art section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.